1. Field of the Invention
The present invention relates generally to methods for fabricating magnetic heads, and more particularly to methods for notching the P1 magnetic pole of such magnetic heads.
2. Description of the Prior Art
One approach to increasing the areal data storage density of magnetic disks is to narrow the width of the data tracks written on the disks, such that more tracks per inch can be written, and therefore more data stored on the disk in a given area. Generally, the width of the base of the P2 magnetic pole tip determines the width of the data track; however, it is also necessary to provide some spacing between adjacent tracks, and the spacing required between data tracks is a function of the strength of the fringing magnetic fields that are created by the magnetic head. In some prior art magnetic heads, the fringing fields can be strong enough to affect data in neighboring data tracks, and the width of a fringing magnetic field can be a significant portion of a data track itself. Therefore, it is desirable to minimize the fringing fields generated by magnetic heads, such that adjacent data tracks can be written more closely together, and the areal data storage density on the disk thereby increased.
One of the fabrication methods that has been undertaken in the prior art to reduce the fringing fields is to notch the P1 magnetic pole, as is known to those skilled in the art. Such P1 pole notching can substantially reduce the fringing magnetic fields generated by the magnetic head, and can thereby increase the areal data storage density on the disk. The standard P1 notching process of the prior art utilizes the previously fabricated P2 pole tip as an etching mask element in the notching process, and the process includes first etching through the write gap layer, typically alumina (Al2O3), and then etching into the P1 pole layer (typically permalloy, a NiFe compound). A problem that initially exists in the prior art P1 notching process is that an argon ion beam was utilized to etch the P1 pole notches, and the alumina write gap layer is significantly more resistant to etching by the argon ion beam than the NiFe material of the P2 pole tip and the P1 layer. Therefore, where an argon ion beam was used in the prior art to conduct the P1 notching step, significant portions of the P2 pole tip were etched away while the beam more slowly etched through, the alumina write gap layer. Thereafter, further portions of the P2 pole tip were etched away while the P1 pole was subsequently notched by the ion beam. As a result, the earlier prior art P1 pole notching process required the initial fabrication of a rather thick P2 pole tip, such that a properly sized P2 pole tip remained following the etching in the P1 notching step utilizing an argon ion beam.
A prior art improvement in P1 notching involves the initial utilization of a first etchant gas species accelerates the etching of the alumina write gap layer and slows down the etching of the NiFe P2 pole tip material. Such a prior art etchant gas is CHF3, and following the use of CHF3 in the etching process to etch through the alumina write gap layer, the etchant gas was changed to argon to notch the P1 pole. As a result, a much smaller portion of the P2 pole tip was etched away during the P1 notching step than was previously the case. This prior art also teaches that a decrease of the NiFe etch rate in CHF3 milling occurs due to the formation of a polymer layer on the surface of the NiFe pole.
A problem that has arisen with the use of CHF3 in the etching process is that it creates excessive polymer deposition. The polymer deposition can cause product contamination and results in the need for frequent cleaning and maintenance of the tooling hardware. Such polymers are apparently created in chemical reactions associated with the ionization of the CHF3 etchant gas, creating a significant problem in the utilization of CHF3 for P1 notching. The present invention avoids the excessive polymer deposition problems of CHF3 while maintaining the benefits of the two-step P1 pole notching process. Specifically, the present invention is a P1 notching process utilizing C2F6 as a preferred substitute for CHF3.
The present invention includes a two-step etching process for notching the P1 pole of the write head element of a magnetic head. In a first step, the preferred embodiment utilizes a combination of C2F6 and argon gases (designated as C2F6/Ar) as the etchant gas to preferentially etch portions of the alumina write gap layer. Thereafter, in the second step, argon is used as the etchant gas to preferentially etch the P1 pole material. The C2F6/Ar etchant gas preferably includes C2F6 gas in a concentration range of from 50% to 90%, with a preferred concentration range being from 70% to 80%. The etching of the alumna write gap layer is preferably conducted with a first echant ion beam angle of from 5xc2x0 to 30xc2x0, and a second etchant ion beam angle of from 65xc2x0 to 85xc2x0.
It is an advantage of the P1 notching process of the present invention that contamination of magnetic head during a P1 notching step is reduced.
It is another advantage of the P1 notching process of the present invention that it avoids frequent cleaning and maintenance of the tooling hardware.
It is a further advantage of the present invention that a two-step P1 notching process has been developed that rapidly etches the write gap layer in a first step and rapidly etches the P1 layer in a second step.
It is yet another advantage of the present invention that a magnetic head is reliably manufactured that has reduced fringing magnetic fields.
It is yet a further advantage of the present invention that a magnetic head has been developed having a right head element that produces reduced fringing magnetic fields, such that the areal data storage density on hard disks can be increased.